If you mean interval as in find out the probability of between two numbers then it’s just P(z-score of bigger number) - P(z-score of smaller number). So example there is a survey on battery power of a certain battery from a company. It’s mean is 1450hrs and it’s standard deviation is 8.5hrs. You want to find out the probability of having a battery with the power 1440hrs and 1465hrs, thus you find the z-scores on both and minus them. P(30/17) - P(-20/17)= 0.84149
